Yeah, you really need to look closely. Because I had the same first reaction as you, only to be disappointed. During the recent stream of garbage in UA articles, I've been regularly writing in my feedback that we don't need more and more subclasses (especially poorly designed ones) and I repeatedly mentioned in my feedback that I wanted to see something unprecedented such as variant class features exactly.
The problem is that there are only VERY FEW variant class features in this UA. Most of the stuff here is not a "variant" which you can choose instead of a core ability of the class. It's a shameless free bump or extra feature which sounds like a first attempt at a 5.5 revision of the PHB.
A real "variant" does not invalidate the PHB version of a character by making it feel inferior for not having the variant... For example, if you add to the game a new way for a Sorcerer to use spell points, that's a boost, not a variant, because a core-only Sorcerer simply has something less than a Sorcerer using this UA article. There is no choice really. The same thing happens if you just add more spells to a class list.
It's a pity because the real variant class features in this article are actually quite interesting, and not just those which you can get at a certain class level instead of the usual PHB class feature at the same level, but also including for example almost all the new Maneuvers, Metamagic and Invocations. Adding them to the game does not make core-only characters obsolete, because the total number of them per character is the same, there really IS a choice for the player, and ignoring the new options does not lead to an inferior character. There has to be a price to pay for every enhancement, otherwise everyone should get the enhancement (and then you're all playing a revised 5.5 version of the game) or none of them.
Now imagine what happens with the "PHB+1" rule in place: if you pick for your "+1" the book with the variant options, you suddendly get a few free boosts for you PC, while players who needed to pick another book have to pay for its options like they always had. How fair is that?